Gray whale abundance monitoring
Twelve complete census surveys of the lagoon were conducted from February 5 to March 30, 2007. The maximum count of adult whales was 217 on 22 February (197 “single” whales and 20 cows with calves). The highest count of single whales was 197 and occurred on 22 February, and the highest cow-calf pairs count was 37 on 17 February. The high count of adult whales was 46% less than the highest recorded count of 407 adult whales on 14 February 1982, and occurred later in the season than 10 of the previous February highest count surveys suggesting a continuing decline in the number of whales utilizing this lagoon and a delay and shortening of the winter occupation of the lagoon by whales. Counts of female calf pairs also demonstrated declines from 137 pairs counted on 14 February 1982 to 37 pairs on 17 February 2007, or a decline of 73%.
Gray whale photo-identification
Photographic data for individual gray whales photographed in Laguna San Ignacio was compared for the periods 1978-1982, 1996-2000, and 2006-2007. The minimum residency time in the lagoon for single adult whales ranged from 2.6 days (95% CI 1.7 – 3.5) in 1996, to 6.8 days (95% CI 3.6 – 10.0) in 2000, to 7.29 days (95% CI 3.67 – 10.91) in 2006-2007, and for females with calves of the year was 19.1 days (95% CI 14.3-23.9) in 1996, to 25.5 days (95% CI 20.1-30.9) in 1999, and 14.50 days (95% CI 11.81 – 17.19) in 2006-2007. The interval between producing calves was estimated from photographic data by Jones (1990) at 2.11 years (SD = 0.0403) for the period 1978 to 1982, and was estimated at 2.82 years (95% CI 2.46-3.16) for the period 1996-2000.
The photographic data indicated that a number of individual whales exhibited obvious signs of mal-nutrition and/or disease that has been termed evidence of the “skinny whale syndrome” (Weller et al. 2000). While most gray whales observed within Laguna San Ignacio appeared to be normal, some individuals possessed noticeable “post cranial depression” and hump in the dorsal neck region of the body. Others were observed with protruding leading edges of their scapula, and concave rather than a convex profiles to their dorsal flank areas.
2007 Community Reunion
Workshop and discussion of Ecosystem Science Program for Eco-Tourism Operators, lagoon fishermen, and local residents held 24 February 2007 at Kuyima facility at Laguna San Ignacio.
- Preliminary report of the 2007 findings was submitted to the International Whaling Commission’s Scientific Committee for review.
- Internet Photo-ID web site to be launched in summer 2007 to allow interned based photo archiving and management, and expanded availability to other gray whale investigators.
- Laguna San Ignacio Ecosystem Science Program Web-Site development initiated. Expected launch in fall 2007.
- Workshop to review 2007 program findings and plans for 2008 to be held at the Autonomous University of Baja California Sur (UABCS) in La Paz in September 2007.(Postpomed until 2008).
- Preliminary benthic inventory surveys supported by Earthwatch Teams under William Megill, University of Bath (In Progress).
- Gray Whale health and condition sampling by Lorenzo Rojas and Teri Rowles supported by NOAA Fisheries Service (In Progress).